2022年2015届高三数学一轮复习38应用举例精品试题 .pdf
应 用 举 例(45 分钟100 分)一、选择题(每小题 5 分,共 40 分)1.如图所示,为了测量某障碍物两侧A,B 间的距离,给定下列四组数据,不能确定A,B 间距离的是()A.,a,b B.,a C.a,b,D.,b【解析】选 A.选项 B中由正弦定理可求b,再由余弦定理可确定AB.选项 C 中可由余弦定理确定AB.选项 D同 B类似.2.(2013 金华模拟)如图,设 A,B 两点在河的两岸,一测量者在A的同侧所在的河岸边选定一点C,测出 AC的距离为 50m,ACB=45,CAB=105 后,就可以计算出A,B 两点间的距离为()A.50m B.50m C.25m D.m【解 析】选A.因 为 ACB=45 ,CAB=105,所 以 CBA=30,在 ABC 中,由 正 弦 定 理,得=,即=,所以 AB=50(m),故选 A.【加固训练】如图所示,为测一建筑物的高度,在地面上选取A,B 两点,从 A,B 两点分别测得建筑物顶端的仰角为 30,45 ,且 A,B 两点间的距离为60m,则该建筑物的高度为()A.(30+30)m B.(30+15)m C.(15+30)m D.(15+15)m【解析】选 A.在 PAB中,PAB=30,APB=15,AB=60,sin15=sin(45-30)=sin45 cos30-cos45sin30=-=,由正弦定理,得=,所以 PB=30(+),所以建筑物的高度为PBsin45=30(+)=(30+30)m.3.(2013 台州模拟)某人向正东方向走xkm后,向右转 150,然后朝新方向走3km,结果他离出发点恰好是km,那么 x 的值为()A.B.2C.或 2D.3【解析】选 C.如图所示,设此人从 A出发,则 AB=xkm,BC=3km,AC=km,ABC=30,由余弦定理,得()2=x2+32-2x 3cos30,整理得 x2-3x+6=0,解得 x=或 2.4.甲、乙两人在同一地平面上的不同方向观测20m高的旗杆,甲观测的仰角为50,乙观测的仰角为40,用 d1,d2分别表示甲、乙两人离旗杆的距离,那么有()A.d1d2B.d120m D.d2tan 40 可知,d160,设最大角为,故对的边长为a+2,因为 sin=,所以=120,由余弦定理得(a+2)2=(a-2)2+a2+a(a-2),即 a2=5a,解得 a=5.所以三边长为3,5,7,S=35sin120=.8.ABC中,AB=12,ACB的平分线 CD把 ABC的面积分成32 两部分,则 cosA 等于()文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 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ZL6W1L5C4O3A.B.C.D.0【思路点拨】先根据角平分线的性质,将面积比转化为三角形中两边的关系,再由正弦定理构造方程求解.【解析】选 C.因为 CD为 ACB的平分线,所以 D到 AC与 D到 BC的距离相等.所以 ACD中 AC边上的高与 BCD中 BC边上的高相等.因为 SACDSBCD=32,所以=.由正弦定理,得=,又因为 B=2A,所以=,=,所以 cosA=.二、填空题(每小题 5 分,共 20 分)9.在?ABCD 中,AB=6,AD=3,BAD=60,则?ABCD 的对角线AC长为,面积为.【解析】在?ABCD中,连接 AC,则 CD=AB=6,ADC=180-BAD=180-60=120.根据余弦定理,得AC=3.?ABCD的面积 S=2SABD=ABAD sin BAD=63sin60 =9.答案:3910.一船向正北航行,看见正西方向有相距10 海里的两个灯塔恰好与它在一条直线上,继续航行半小时后,看见 一灯塔在船的南偏西60 方向,另一灯塔在船的南偏西75 方向,则这只 船的速度是每小时.【解析】如图,依题意有BAC=60 ,BAD=75,所以 CAD=CDA=15,从而 CD=CA=10,在直角三角形ABC中,可得 AB=5,于是这只船的速度是=10(海里/小时).答案:10 海里文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 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ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O311.(2013 咸阳模拟)在 ABC中,AD 为 BC边上的中线,且 AC=2AB=2AD=4,则 BD=.【解析】设 BD=DC=x,因为 ADB+ADC=180,所以 cosADB=-cosADC,又 AC=2AB=2AD=4,由余弦定理得=-,解得 x=(x=-舍去),故 BD=.答案:12.(能力挑战题)某城市为加强对建筑文物的保护,计划对该市的所有建筑文物进行测量,如图是一座非常著名的古老建筑,其中 A 是烟囱的最高点,选择一条水平基线HG,使得 H,G,B 三点在同一条直线上,AB 与水平基线 HG垂直,在相距为60 m的 G,H两点用测角仪测得A的仰角 ACE,ADE分别为 75,30,已知测角仪器的高BE=1.5 m,则 AB=m(参考数据:1.4,1.7).【解析】因为 ACE=75,ADC=30,所以 CAD=45,在 ACD中,CD=60,由正弦定理得=,则 AC=30.在 Rt AEC 中,AE=ACsin75,而 sin75 =sin(30 +45)=,所以AE=15(1+)40.5(m),故AB=AE+EB=40.5+1.5=42(m).答案:42 三、解答题(13 题 12 分,14 15 题各 14 分)13.(2014 绍兴模拟)如图,在 ABC中,B=,BC=2,点 D在边 AB上,AD=DC,DE AC,E为垂足.(1)若 BCD的面积为,求 CD的长.文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 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HK6L7P8Z5O2 ZL6W1L5C4O3(2)若 DE=,求角 A的大小.【解析】(1)由已知得SBCD=BC BDsinB=,又 BC=2,sinB=,得 BD=,在 BCD中,由余弦定理得CD=,所以 CD的长为.(2)方法一:因为 CD=AD=,在 BCD中,由正弦定理得=,又 BDC=2 A,得=,解得 cosA=,所以 A=即为所求.方法二:在 ABC中,由正弦定理得=,又由已知得,E 为 AC中点,所以 AC=2AE,所以 AE sinA=sinB=,又=tanA=,所以 AE sinA=DEcosA=cosA=,得 cosA=,所以 A=即为所求.14.(2014 温州模拟)在 ABC中,角 A,B,C 所对的边分别为a,b,c,a(cosC+sinC)=b.(1)求角 A的大小.(2)若 a=1,SABC=,求 b,c 的值.【解析】(1)由正弦定理,得 sinA(cosC+sinC)=sinB.又 sinB=sin(A+C),化简得:sinAsinC=cosAsinC.文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3因为 sinC 0,故 tanA=,A=.(2)根据题意得把 A=,a=1 代入解得或【方法技巧】三角形面积公式的应用原则(1)对于面积公式S=absinC=acsinB=bcsinA,一般是已知哪一个角就使用与该角正弦值有关的面积公式.(2)与面积有关的问题,一般要用到正弦定理或余弦定理进行边和角的转化.15.(能力挑战题)(2013 江苏高考)如图,游客从某旅游景区的景点A处下山至 C处有两种路径.一种是从A沿直线步行到C,另一种是先从A沿索道乘缆车到B,然后从 B沿直线步行到C.现有甲、乙两位游客从A处下山,甲沿 AC匀速步行,速度为 50m/min.在甲出发2min 后,乙从 A乘缆车到B,在 B处停留 1min 后,再从 B匀速步行到C.假设缆车匀速直线运动的速度为130m/min,山路 AC长为 1260m,经测量,cosA=,cosC=.(1)求索道 AB的长.(2)问:乙出发多少分钟后,乙在缆车上与甲的距离最短?(3)为使两位游客在C处互相等待的时间不超过3 分钟,乙步行的速度应控制在什么范围内?【思路点拨】(1)利用正弦定理确定出AB的长.(2)先设再建立时间t 与甲、乙间距离d 的函数关系式,利用关系式求最值.(3)利用条件“使两位游客在C处互相等待的时间不超过3 分钟”建立不等关系求解.【解析】(1)在 ABC中,因为 cosA=,cosC=,所以 sinA=,sinC=.从而 sinB=sin-(A+C)=sin(A+C)=sinAcosC+cosAsinC=+=.文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3由正弦定理=,得AB=sinC=1040(m).所以索道AB的长为 1040m.(2)假设乙出发t 分钟后,甲、乙两游客距离为d,此时,甲行走了(100+50t)m,乙距离A 处 130tm,所以由余弦定理得d2=(100+50t)2+(130t)2-2 130t (100+50t)=200(37t2-70t+50),因 0t,即 0t 8,故当 t=(min)时,甲、乙两游客距离最短.(3)由正弦定理=,得 BC=sinA=500(m).乙从 B出发时,甲已走了50(2+8+1)=550(m),还需走 710m才能到达C.设乙步行的速度为vm/min,由题意得-3-3,解得v,所以为使两位游客在C处互相等待的时间不超过3 分钟,乙步行的速度应控制在(单位:m/min)范围内.【加固训练】如图,甲船以每小时30海里的速度向正北方航行,乙船按固定方向匀速直线航行.当甲船位于 A1处时,乙船位于甲船的北偏西105方向的B1处,此时两船相距20 海里,当甲船航行20 分钟到达A2处时,乙船航行到甲船的北偏西120方向的 B2处,此时两船相距10海里.问:乙船每小时航行多少海里?【解析】如图,连接 A1B2,由已知 A2B2=10,文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2 ZL6W1L5C4O3文档编码:CN1Q2F8G9L5 HK6L7P8Z5O2